hydrocephalus

noun

hy·​dro·​ceph·​a·​lus ˌhī-drō-ˈse-fə-ləs 

variants or less commonly hydrocephaly

ˌhī-drō-ˈse-fə-lē 

: an abnormal increase in the amount of cerebrospinal fluid within the cranial cavity (as from obstructed flow, excess production, or defective absorption) that is accompanied by expansion of the cerebral ventricles and often increased intracranial pressure, skull enlargement, and cognitive decline

Examples of hydrocephalus in a Sentence

Recent Examples on the Web

The family's attorney, Robert Glassman, said the little 4-year-old boy is nonverbal, has autism, spina bifida and hydrocephalus. —CBS News, 10 Apr. 2026

Her son, who is referred to as J.M. in the complaint, is nonverbal and autistic and has spina bifida and hydrocephalus. —Clara Harter, Los Angeles Times, 9 Apr. 2026

The mother told police about the boy's long medical history, including being diagnosed with cerebral palsy, hip dysplasia and hydrocephalus. —Jade Jackson, IndyStar, 27 Mar. 2026

In May, Joel canceled all forthcoming shows, announcing that he’d been diagnosed with a brain disorder known as normal pressure hydrocephalus. —Jami Ganz, New York Daily News, 3 Jan. 2026

Word History

Etymology

New Latin hydrocephalus, from Late Latin, hydrocephalic, adjective, from Greek hydrokephalos, from hydr- + kephalē head — more at cephalic

First Known Use

1670, in the meaning defined above

Kids Definition

hydrocephalus

noun

hy·​dro·​ceph·​a·​lus ˌhī-drō-ˈsef-ə-ləs 

variants also hydrocephaly

-ˈsef-ə-lē 

: an abnormal condition in which an increased amount of cerebrospinal fluid causes an increase in the size of the ventricles of the brain and the size of the skull and the wasting away of the brain

Medical Definition

hydrocephalus

noun

hy·​dro·​ceph·​a·​lus -ˈsef-ə-ləs, British also -ˈkef- 

plural hydrocephali -ˌlī 

: an abnormal increase in the amount of cerebrospinal fluid within the cranial cavity (as from obstructed flow, excess production, or defective absorption) that is accompanied by expansion of the cerebral ventricles and often increased intracranial pressure, skull enlargement, and cognitive decline